From d57c61959c5e5b661892ae6f65cfdefbac671ecb Mon Sep 17 00:00:00 2001
From: Heng Sin Low <hengsin@gmail.com>
Date: Mon, 14 Dec 2009 04:34:16 +0000
Subject: [PATCH] 
 https://sourceforge.net/tracker/?func=detail&aid=2913965&group_id=176962&atid=879335
 - add api to support the use of database specific paging feature to return a
 subset of the query result.

---
 .../org/compiere/db/AdempiereDatabase.java    | 17 +++++++-
 base/src/org/compiere/db/DB_Oracle.java       |  8 ++++
 base/src/org/compiere/db/DB_PostgreSQL.java   | 41 +++++++++----------
 .../compiere/dbPort/Convert_PostgreSQL.java   |  2 +
 4 files changed, 46 insertions(+), 22 deletions(-)

diff --git a/base/src/org/compiere/db/AdempiereDatabase.java b/base/src/org/compiere/db/AdempiereDatabase.java
index 3ac3e42228..7acc0ae848 100644
--- a/base/src/org/compiere/db/AdempiereDatabase.java
+++ b/base/src/org/compiere/db/AdempiereDatabase.java
@@ -301,6 +301,21 @@ public interface AdempiereDatabase
 	 * Default sql use to test whether a connection is still valid
 	 */
 	public final static String DEFAULT_CONN_TEST_SQL = "SELECT Version FROM AD_System";
-	
+
+	/**
+	 * Is the database have sql extension that return a subset of the query result
+	 * @return boolean
+	 */
+	public boolean isPagingSupported();
+
+	/**
+	 * modify sql to return a subset of the query result
+	 * @param sql
+	 * @param start
+	 * @param end
+	 * @return
+	 */
+	public String addPagingSQL(String sql, int start, int end);
+
 }   //  AdempiereDatabase
 
diff --git a/base/src/org/compiere/db/DB_Oracle.java b/base/src/org/compiere/db/DB_Oracle.java
index 153bdfdb82..ce62e17424 100644
--- a/base/src/org/compiere/db/DB_Oracle.java
+++ b/base/src/org/compiere/db/DB_Oracle.java
@@ -1108,6 +1108,14 @@ public class DB_Oracle implements AdempiereDatabase
 	public boolean isQueryTimeoutSupported() {
 		return true;
 	}
+	
+	public String addPagingSQL(String sql, int start, int end) {
+		String newSql = "SELECT * FROM (" + sql + ") WHERE ROWNUM BETWEEN " + start + " AND " + end;
+		return newSql;
+	}
 
+	public boolean isPagingSupported() {
+		return true;
+	}
 
 }   //  DB_Oracle
diff --git a/base/src/org/compiere/db/DB_PostgreSQL.java b/base/src/org/compiere/db/DB_PostgreSQL.java
index c55fa7e0ec..f7f3b086c5 100755
--- a/base/src/org/compiere/db/DB_PostgreSQL.java
+++ b/base/src/org/compiere/db/DB_PostgreSQL.java
@@ -84,16 +84,17 @@ public class DB_PostgreSQL implements AdempiereDatabase
 	/** Cached Database Name	*/
 	private String			m_dbName = null;
         
-        private String				m_userName = null;
-        	/** Connection String       	*/
+    private String				m_userName = null;
+    
+    /** Connection String       	*/
 	private String          		m_connectionURL;
         
-        private boolean                         m_supportAlias = false;
-            
 	/**	Logger			*/
 	private static CLogger			log	= CLogger.getCLogger (DB_PostgreSQL.class);
     
-     private static int              m_maxbusyconnections = 0;
+    private static int              m_maxbusyconnections = 0;
+     
+    public static final String NATIVE_MARKER = "NATIVE_"+Database.DB_POSTGRESQL+"_KEYWORK";
 
 	/**
 	 *  Get Database Name
@@ -791,21 +792,19 @@ public class DB_PostgreSQL implements AdempiereDatabase
 		return false;
 	}
 
+	/**
+	 * Implemented using the limit and offset feature. use 1 base index for start and end parameter
+	 * @param sql
+	 * @param start
+	 * @param end
+	 */
+	public String addPagingSQL(String sql, int start, int end) {
+		String newSql = sql + " " + NATIVE_MARKER + "LIMIT " + ( end - start + 1 )
+			+ "  " + NATIVE_MARKER + "OFFSET " + (start - 1);
+		return newSql;
+	}
 
-
-        /*
-         public boolean getSupportAlias()
-        {             
-             
-		if (s_driver == null)
-		{
-			s_driver = new org.postgresql.Driver();
-                        if(s_driver.getVersion().indexOf("PostgreSQL 8.2") != -1)
-                        return true;
-                       
-		}
-             return false;
-
-        }*/
-
+	public boolean isPagingSupported() {
+		return true;
+	}
 }   //  DB_PostgreSQL
diff --git a/base/src/org/compiere/dbPort/Convert_PostgreSQL.java b/base/src/org/compiere/dbPort/Convert_PostgreSQL.java
index dfdf9783b8..df186ba804 100644
--- a/base/src/org/compiere/dbPort/Convert_PostgreSQL.java
+++ b/base/src/org/compiere/dbPort/Convert_PostgreSQL.java
@@ -22,6 +22,7 @@ import java.util.Vector;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import org.compiere.db.DB_PostgreSQL;
 import org.compiere.model.MSysConfig;
 import org.compiere.util.CLogger;
 import org.compiere.util.DB;
@@ -107,6 +108,7 @@ public class Convert_PostgreSQL extends Convert_SQL92 {
 		
 		String statement = replaceQuotedStrings(sqlStatement, retVars);
 		statement = convertWithConvertMap(statement);
+		statement = statement.replace(DB_PostgreSQL.NATIVE_MARKER, "");
 		
 		String cmpString = statement.toUpperCase();
 		boolean isCreate = cmpString.startsWith("CREATE ");